Method and apparatus for formulating image data, method and apparatus for converting image data, method and apparatus for formulating holographic stereogram, recording medium and data transmitting method

ABSTRACT

In a system in which images having parallax data, and which are made up of plural images containing the parallax information, are processed with viewing point conversion, and the resulting new images having parallax data are used, as in a system of generating a holographic stereogram, a unit for generating the images having parallax data is to be independent from other unit or units. To this end, the information necessary to perform viewing point conversion processing of converting the viewing point for an object is attached to images having parallax data when the images having parallax data have been produced. When the images having parallax data is exchanged between the unit for generating the images having parallax data and other unit or units, the exchanged images having parallax data need to be those to which the information has been attached.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to an image data generating method andapparatus for generating data of a parallax image string used forgenerating a holographic stereogram. This invention also relates to animage data converting method and apparatus for processing data of anparallax image string with viewing point conversion to generate data ofa new parallax data. This invention also relates to a method andapparatus for generating a holographic stereogram based on data of theparallax image string. This invention also relates to a recording mediumhaving stored therein data of the parallax image string used forgenerating a holographic stereogram. This invention similarly relates toa method for transmitting data of the parallax image string used forformulating a holographic stereogram.

[0003] 2. Description of the Related Art

[0004] A holographic stereogram is prepared by sequentially recording alarge number of images, as original images, on a sole recording mediumfor hologram as a strip-shaped or dot-shaped element hologram. Theseimages have been obtained by sequentially imaging an object fromdifferent viewing points.

[0005] For example, in generating a holographic stereogram having theparallax information only in the transverse direction, an object 100 issequentially imaged from different viewing points of the transversedirection to produce a parallax image string 101 made up of pluralimages having the parallax information only in the transverse direction.The images 102 making up the parallax image string 101 are sequentiallyrecorded as strip-shaped elementary holograms on a recording medium forhologram 103 so that these images 102 will be consecutive to one anotherin the transverse direction. This yields a holographic stereogramcarrying the parallax information in the transverse direction.

[0006] In this holographic sterogram, in which the information of theplural images 102, obtained on sequentially imaging the object fromplural viewing points of the transverse direction, is sequentiallyrecorded as strip-shaped elementary holograms so that the images 102will be consecutive to one another, two-dimensional images, as viewed byleft and right eyes, differ from each other if this holographicstereogram is viewed by a viewer with both eyes. This causes the viewerto perceive the parallax so that a three-dimensional image isreproduced.

[0007] Meanwhile, the string of parallax images, from which theholographic stereogram is derived, is produced by translating a camera104 directed to the object 100, as the camera 104 is oriented in a fixeddirection, and by imaging the object 100 a large number of times. Thatis, the camera 104, oriented towards the object 100, is translated froma position in which the object 100 enters an imaging range by the camera104, to a position in which the object 100 is moved out of the imagingrange by the camera 104, and by imaging the object a large number oftimes during this time interval, whereby a parallax image string, fromwhich is originated the holographic stereogram, is produced. Meanwhile,this system of translating the camera 104 as the latter is kept in afixed direction is termed a straight track system.

[0008] It is noted that, in a holographic stereogram, the relativeposition between the viewing point of the camera 104 and the object 100at the time of imaging is kept in the reproduced image of the generatedhologram as well. Thus, if the parallax image string, produced asdescribed above, is directly used for generating a holographicstereogram, a reproduced image Z is formed at a more recessed positionthan the hologram plane Ha of the holographic stereogram H. Therefore,with this holographic stereogram, a reproduced image Z is distorted orblurred, unless a viewer sees the reproduced image Z, with the viewingpoint S set on the hologram plane Ha, so that the distance dO betweenthe reproduced image Z and the reproduced image Z of the viewercoincides with the distance d between the object 100 and a viewing pointof the camera 104 at the time of imaging.

[0009] Thus, for dissolving this problem in the preparation of theholographic stereogram, it is necessary to perform viewing pointconversion processing on data of the original parallax image string sothat the reproduced image Z will be formed in the vicinity of thehologram plane Ha of the holographic stereogram H, as shown in FIG. 4.By this viewing point converting processing, the reproduced image Z isfree of distortion or blurring even if the viewing point S is set at aposition remote from the hologram plane Ha.

[0010] In our Japanese Patent Application H-8-170018, corresponding toJapanese Laying-Open Patent H-10-20754, the present Assignee hasproposed a system of performing viewing point conversion processing ondata of the parallax image string to generate a holographic stereogram.In this system, an object is imaged from different viewing points toprepare data of a parallax image string, this data of the parallax imagestring is processed with viewing point conversion and the resultingconverted data is used to generate a holographic stereogram.

[0011] This system, however, tends to be bulky on a whole since it ismade up of a mechanism for generating data of a parallax image string, amechanism for viewing point conversion processing and a mechanism forgenerating the holographic stereogram.

SUMMARY OF THE INVENTION

[0012] It is therefore an object of the present invention to provide asystem for performing viewing point conversion on data of a parallaximage string made up of plural images having the parallax information,such as the system for generating a holographic stereogram, in which amechanism for generating the data of the parallax image string can beindependent from other mechanisms.

[0013] In one aspect, the present invention provides a image dataprocessing system including means for formulating images having parallaxdata, made up of a plurality of images of an object from differentviewing points, and data attachment means for attaching the informationnecessary for performing the viewing point conversion processing ofconverting the viewing points for the object on the images havingparallax data.

[0014] In another aspect, the present invention provides a method forprocessing image data including generating images having parallax data,made up of a plurality of images of an object from different viewingpoints, and attaching the information necessary for performing theviewing point conversion processing of converting the viewing points forthe object on the images having parallax data to the images havingparallax data.

[0015] In still another aspect, the present invention provides an imagedata converting system including data receiving means for receivingimages having parallax data, made up of a plurality of images of anobject from different viewing points, and the information necessary forperforming the viewing point conversion processing of converting theviewing points for the object on the images having parallax data, andviewing point conversion means for performing viewing point conversionprocessing, on the basis of the information, on the images havingparallax data, as received from the data receiving means.

[0016] In still another aspect, the present invention provides an imagedata converting method including inputting images having parallax data,made up of a plurality of images of an object from different viewingpoints, and the information necessary for performing the viewing pointconversion processing of converting the viewing points for the object onthe images having parallax data, to computing processing means, andperforming viewing point conversion processing, on the basis of theinformation, on the images having parallax data.

[0017] In still another aspect, the present invention provides aholographic stereogram printing system including data receiving meansfor receiving images having parallax data, made up of a plurality ofimages of an object from different viewing points, and the informationnecessary for performing the viewing point conversion processing ofconverting the viewing points for the object on the images havingparallax data, and viewing point conversion means for performing viewingpoint conversion processing, on the basis of the information, on theimages having parallax data, as received from the data receiving means,and means for generating a holographic stereogram using new imageshaving parallax data, as obtained on executing viewing point conversionprocessing by the viewing point conversion means.

[0018] In still another aspect, the present invention provides a methodfor generating a holographic stereogram including inputting imageshaving parallax data, made up of a plurality of images of an object fromdifferent viewing points, and the information necessary for performingthe viewing point conversion processing of converting the viewing pointsfor the object on the images having parallax data, to computingprocessing means, performing viewing point conversion processing, on thebasis of the information, on the images having parallax data, by thecomputing processing means, to produce new images having parallax data,and using the new images having parallax data for generating aholographic stereogram.

[0019] In still another aspect, the present invention provides acomputer-readable recording medium in which there are stored imageshaving parallax data, made up of plural images of an object fromdifferent viewing points, and data required for executing the viewingpoint conversion processing of converting the viewing points for theobject on the images having parallax data.

[0020] In yet another aspect, the present invention provides a datatransmission method including collectively transmitting images havingparallax data, made up of a plurality of images of an object fromdifferent viewing points, and the information necessary for performingthe viewing point conversion processing of converting the viewing pointsfor the object on the images having parallax data.

[0021] According to the present invention, as described above, it ispossible, in a system in which images having parallax data, and whichare made up of plural images having the parallax information, areprocessed with viewing point conversion, and the resulting new imageshaving parallax data are used, as in a system of generating aholographic stereogram, to provide a unit for generating data of aparallax image string independently of other unit or units.

[0022] Thus, according to the present invention, a studio for imaging aparallax image string, a data processing center for viewing pointconversion and a printing laboratory for generating a holographicstereogram may be provided independently of one another.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1 schematically shows a method for generating a holographicstereogram.

[0024]FIG. 2 shows a method for imaging a parallax image string by thestraight track system.

[0025]FIG. 3 shows the manner in which a reproduced image of aholographic stereogram generated without viewing point conversionprocessing is being viewed.

[0026]FIG. 4 shows the manner in which a reproduced image of aholographic stereogram generated on viewing point conversion processingis being viewed.

[0027]FIG. 5 is a block diagram showing an illustrative structure of aholographic stereogram generating system.

[0028]FIG. 6 is a block diagram showing an illustrative structure of animage data generating system according to the present invention.

[0029]FIG. 7 shows a method for imaging a parallax image string by thestraight track system.

[0030]FIG. 8 shows a method for imaging a parallax image string by thepanning system.

[0031]FIG. 9 shows a method for imaging a parallax image string by therotating system.

[0032]FIG. 10 shows a method for imaging a parallax image string by there-centering system.

[0033]FIG. 11 is a block diagram showing an illustrative structure of aholographic stereogram generating device according to the presentinvention.

[0034]FIG. 12 is a block diagram showing an illustrative structure of aholographic stereogram generating unit.

[0035]FIGS. 13A, 13B shows an illustrative structure showing an opticalsystem of a holographic stereogram printer.

[0036]FIG. 14 shows the manner in which a studio for imaging a parallaximage string and a printing laboratory for generating a holographicstereogram are provided independently of each other.

[0037]FIG. 15 shows the manner in which a studio for imaging a parallaximage string, a data processing center for performing viewing pointconversion processing and a printing laboratory for generating aholographic stereogram are provided independently of one another.

[0038]FIG. 16 shows the method for imaging a parallax image string bythe re-centering system.

[0039]FIG. 17 illustrates the viewing point conversion processing andspecifically the relation between a parallax image string for exposureGE and an original parallax image string GD.

[0040]FIG. 18 illustrates the viewing point conversion processing andspecifically the relation between one of images g21 of a parallax imagestring for exposure GE and respective images g11, g12, . . . , g1m of anoriginal parallax image string GD.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] Referring to the drawings, preferred embodiments of the presentinvention will be explained in detail. Although the present invention isapplied to a holographic stereogram generating system, by way of anexample, in the following explanation, the method and apparatus forformulating image data, and the method and apparatus for convertingimage data according to the present invention, can be extensivelyapplied to any technical field in need of viewing point conversionprocessing. For example, there are occasions wherein the viewing pointconversion processing is executed when displaying a stereo image on adisplay device by taking advantage of the parallax. The method andapparatus for formulating image data and the method and apparatus forconverting image data according to the present invention can be appliedto such case.

[0042] Holographic Stereogram Generating System

[0043] First, the application of the present invention to a holographicstereogram generating system, embodying the present invention, isexplained.

[0044] In this holographic stereogram geneerating system, data of aparallax image string, having attached thereto the information necessaryfor performing the viewing point conversion processing, is generated byan image data generating device 1 of the present invention, as shown inFIG. 5. The generated data is delivered, via a recording medium or anetwork etc, to a holographic stereogram generating device 2 of thepresent invention. The holographic stereogram generating device 2performs viewing point conversion processing on the data received viarecording medium or network etc to generate new data of the parallaximage string to generate a holographic stereogram. The image datagenerating device 1 and the holographic stereogram generating device 2making up such system is hereinafter explained in detail.

[0045] Referring to FIG. 6, the image data generating device 1 includesa parallax image string data generating unit 3 and a data attachmentunit 4. The data attachment unit 4 also attaches the informationnecessary for performing viewing point conversion processing on the dataof the parallax image string to the data of the parallax image stringformulated by the parallax image string data generating unit 3.

[0046] The parallax image string data generating unit 3 is made up of animaging device for imaging a parallax image string made up of pluralimages of the object from different viewing points, and a computer forconverting the image formed by the imaging device into data of e.g., apre-set two-dimensional image format. That is, the parallax image stringdata generating unit 3 images the object by the imaging device fromplural different viewing points, and captures the images, as shot by theimaging device, into a computer, in order to formulate data of theparallax image string.

[0047] Among the imaging methods for the parallax image string, thereare, for example, a straight track system, a panning system, a rotatingsystem and a re-centering system. Although the parallax image stringused for formulation of the holographic stereogram may be imaged by anyof these systems, it is necessary to change the technique of viewingpoint conversion processing with the particular imaging system used.

[0048] In the straight track system, the a camera 11, directed to theobject 10, is translated along a straight rail, as the camera ismaintained in a fixed direction, to image the object a large number oftimes from different positions, as shown in FIG. 7. That is, whenimaging a parallax image string by the straight track system, thecameral 1 directed to the object 10 is translated, from a position inwhich the object 10 enters the imaging range of the camera 11, to aposition in which the objects departs the imaging range, to image theobject a large number of times during this movement.

[0049] In the panning system, the camera 11 is translated along astraight rail, as the direction of the camera 11 is changed so that thecamdera is perpetually directed to the center of the object 10, and theobject 10 is shot from different positions, as shown in FIG. 8. That is,when imaging a parallax image string by the panning system, the camera11 directed to the object 10 is translated, as the camera is pannedtowards the center of the object 10, to image the object a large numberof times during this camera movement.

[0050] In the panning system, the image can be improved in effectiveresolution by the camera panning than is possible with the straighttrack system. However, in generating a planar-shaped holographicstereogram from a parallax image string as shot by the panning system,it is necessary to correct the keystone distortion contained in theparallax image string. It is noted that the technique of viewing pointconversion processing when generating a holographic stereogram from theparallax image string as shot by the panning system is described in, forexample, Japanese Patent Application H-8-302691, corresponding to theJapanese Laying-Open Patent H-10-143058.

[0051] In the rotating system, the camera 11 directed to the center ofthe object 10 is moved along an arcuate path to image a parallax imagestring. In the rotating system, since the camera 11 is directed at alltimes to the center of the object 10, the image can be improved ineffective resolution than in the straight track system. However, if aplanar-shaped holographic stereogram is to be formulated from a parallaximage string as shot by the rotating system, the keystone distortioncontained in the parallax image string needs to be corrected as in thecase of the panning system. The technique for viewing point conversionprocessing when formulating the holographic stereogram from the parallaximage string as shot by the rotating system is described in, forexample, the Japanese Patent Application H-8-170018 corresponding toJapanese Laying-Open Patent H-10-20754.

[0052] In the re-centering system, the camera 11 is translated along astraight rail to shoot the object 10 a large number of times fromdifferent positions and, during the imaging operation, a lens 12 of thecamera 10 is moved in agreement with the shooting position so that theimage of the object 10 will be perpetually located at the center of animaging plane 13, as shown in FIG. 10. That is, in the re-centeringsystem, the object 10 is projected at all times on the center of animaging plane 13 of the camera 11 for imaging, by varying the relativeposition between the lens 12 and the imaging plane 13 of the camera 11in agreement with the movement of the main body unit of the camera 11.In the re-centering system, the image obtained on shooting can beimproved without producing the keystone distortion.

[0053] The parallax image string data generating unit 3 captures theimages, obtained by imaging the object 10 by the above-mentionedtechnique, into the computer, to convert the images into data of thetwo-dimensional image format to formulate an image file. It is notedthat the format of the image file is optional and may, for example, bethe format of a BMP or TIFF. In preparing the image file, the data mayalso be compressed, using an image compressing technique, such as JPEG.In particular, since the parallax image string is made up of images asshot at proximate viewing point positions, the respective images ingeneral exhibit extremely high correlation, so that, if the imagecompression technique exploiting the motion prediction, such as MPEG, isused, the data can be compressed with highly efficiency to reduce thedata volume significantly.

[0054] The respective images, obtained on imaging the object 10 asdescribed above, are converted into data of the two-dimensional imageformat to formulate an image file. Thus, the parallax image string datagenerating unit 3 formulates plural image files as data of the parallaximage string. In the following explanation, these plural image files,formulated as described above, are collectively termed a parallax imagestring file.

[0055] That is, if the object 10 is imaged by an imaging device from 500different viewing points, the parallax image string data generating unit3 formulates a parallax image string file made up of 500 image files.Although it is assumed here that an image is handled as an image file,and a parallax image string file is made up of a large number of imagefiles, it is possible with the present invention to collect pluralimages into a sole image file.

[0056] In the above-described embodiment, the iobject 100 is actuallyimaged to generate a parallax image string file. Alternatively, computergraphics may also be used to formulate a parallax image string file.That is, the parallax image string data generating unit 3 is also ableto use the computer graphics function by a computer in place of theimaging by an imaging device as described above.

[0057] If the parallax image string file is to be generated using thecomputer graphics, the object 10 and the camera 11 are placedimaginarily in the computer graphics space and the camera 11 is moved ata pre-set pitch to image the object 10 a large number of times fromdifferent positions. Stated differently, the viewing point of the camera11 is moved at a pre-set pitch and data of plural images havingdifferent viewing points are formulated by rendering the images of theobject 10 as seen from the different viewing points. By so doing, it issimilarly possible to generate a parallax image string file comparableto the parallax image string file obtained on converting the actuallyshot images of the object 10 into data of the two-dimensional imageformat.

[0058] In the image data generating device 1 embodying the presentinvention, the information necessary to effect viewing point conversionprocessing on the parallax image string file formulated by the parallaximage string data generating unit 3 is appended by the data attachmentunit 4 to the formulated parallax image string file.

[0059] Specifically, the data attachment unit 4 formulates a headerfile, having stored therein the information necessary for applying theviewing point conversion processing, and attaches the header file to aparallax image string file. In the following explanation, the parallaximage string file, having the attached header file, is termed thepre-viewing-point conversion parallax image string data file. That is,the pre-viewing-point conversion parallax image string data filecontains a header file and an image file of respective images making upa parallax image string. Preferably, the information on the conditionsfor formulating a holographic stereogram is also contained in the headerfile. The information stored in the header file will be explained laterby giving specified examples.

[0060] The function of the data attachment unit 4 may be implemented bya computer used for formulating the parallax image string file by theparallax image string data generating unit 3. That is, when the parallaximage string file is to be formulated by the computer, a header file issimultaneously prepared and attached to the parallax image string fileto prepare the pre-viewing-point conversion parallax image string datafile.

[0061] The image data generating device 1 formulates thepre-viewing-point conversion parallax image string data file, comprisedof a parallax image string file and a header file attached thereto, asdescribed above. This pre-viewing-point conversion parallax image stringdata file is delivered, via a recording medium or a network, to theholographic stereogram generating device 2.

[0062] Meanwhile, a recording medium, as a mediator for delivery of thepre-viewing-point conversion parallax image string data file, is arecording medium according to the present invention, that is a recordingmedium having stored therein the pre-viewing-point conversion parallaximage string data file, made up of data of the parallax image stringcomprised of plural images of the object from different viewing points,that is parallax image string file, and data necessary for performingviewing point conversion processing of changing the viewing points forthe object 10 on the parallax image string data, that is header file.

[0063] The recording medium in which the pre-viewing-point conversionparallax image string data file is stored may be any suitable recordingmedium, such as an optical disc, a magneto-optical disc, a magnetic discor a magnetic tape. In delivering the pre-viewing-point conversionparallax image string data file by data transmission on a network, thetype of the network may be optionally selected, such that the data filemay be delivered over the Internet.

[0064] The holographic stereogram generating device 2, to which thepre-viewing-point conversion parallax image string data file isdelivered from the image data generating device 1, includes a datareceiving unit 21, a viewing point conversion unit 22, and a holographicstereogram generating unit 23, as shown in FIG. 11.

[0065] The data receiving unit 21 is used for receiving thepre-viewing-point conversion parallax image string data file.Specifically, if the pre-viewing-point conversion parallax image stringdata file is to be received over the Internet, the data receiving unit21 is constituted by a communication device, such as a terminal adapteror modem. Also, if the pre-viewing-point conversion parallax imagestring data file is to be received via a recording medium, the datareceiving unit 21 is constituted by a driving device adapted to read outdata from the recording medium.

[0066] The data receiving unit 21 delivers the pre-viewing-pointconversion parallax image string data file, received via the recordingmedium or the network etc, to the viewing point conversion unit 22. Theviewing point conversion unit is a computer having stored therein aviewing point conversion program. The viewing point conversion unit 22executes this viewing point conversion program to perform viewing pointconversion processing on the data of the parallax image string stored inthe pre-viewing-point conversion parallax image string data file. Atthis time, the viewing point conversion unit 22 executes the viewingpoint conversion processing based on the information stored in theheader file in the pre-viewing-point conversion parallax image stringdata file. This viewing point conversion processing will be explainedlater by giving a specified example.

[0067] As the result of the viewing point conversion processing,executed on the basis of the information stored in the header file ofthe pre-viewing-point conversion parallax image string data file, theviewing point conversion unit 22 outputs a header file and a newparallax image string file, prepared by the viewing point conversionprocessing. Meanwhile, since the new parallax image string file,prepared by the viewing point conversion processing, performed by theviewing point conversion unit 22, is a file of images for light exposureat the time of preparation of the holographic stereogram, this newparallax image string file, prepared by the viewing point conversionprocessing, performed by the viewing point conversion unit 22, is hereintermed an image string file for light exposure. The header file and theimage string file for light exposure are collectively termed apost-viewing-point conversion parallax image string data file.

[0068] From the viewpoint solely of formulating the holographicstereogram, it is unnecessary to attach a header file to thepost-viewing-point conversion parallax image string data file. However,attachment of the header file to the post-viewing-point conversionparallax image string data file gives rise to a merit that theconditions under which the viewing point conversion processing has beenexecuted can be known on late checking of the post-viewing-pointconversion parallax image string data file.

[0069] If a header file is to be attached to the post-viewing-pointconversion parallax image string data file, the information on the imagestring file for light exposure, such as the name of the image stringfile for light exposure or the date of preparation thereof, ispreferably included in the header file. If the information on theparallax image string for light exposure is appended to the header file,it can be comprehended which parallax image string for light exposure isstored, simply on checking the header file.

[0070] The post-viewing-point conversion parallax image string datafile, prepared by the viewing point conversion unit 22 as describedabove, is delivered to the holographic stereogram generating unit 23.The holographic stereogram generating unit 23 formulates the holographicstereogram based on the received post-viewing-point conversion parallaximage string data file.

[0071] A specified example of the holographic stereogram generating unit23, generating the holographic stereogram on reception of thepost-viewing-point conversion parallax image string data file asdescribed above, is now explained in detail. Meanwhile, the holographicstereogram generating unit 23, now explained, directly outputs afilm-shaped recording medium for hologram, having interference fringesof the object light and the reference light, recorded thereon, as aholographic stereogram. The holographic stereogram, comprised of theinterference fringes of the object light and the reference light,directly recorded on the recording medium for hologram, is generallytermed a one-step holographic stereogram.

[0072] Referring to FIG. 12, the holographic stereogram generating unit23 includes a control computer 24 for controlling the holographicstereogram generating unit in its entirety, a holographic stereogramprinter 25, having the optical system for formulating the holographicstereogram, and an image data furnishing device 26 for supplying imagedata of an image for light exposure to the holographic stereogramprinter 25.

[0073] When recording an image on the recording medium for a hologram,the image data furnishing device 26 sequentially reads out data for oneimage file, from the image string file for light exposure constitutingthe post-viewing-point conversion parallax image string data filegenerated by the viewing point conversion unit 22 as described above, toroute the image data to the holographic stereogram printer 25. Whensending image data for one image to the holographic stereogram printer25, the image data furnishing device 26 sends out a timing signalindicating that effect to the control computer 24.

[0074] Based on the timing signal from the image data furnishing device26, the control computer 24 drives the holographic stereogram printer25. Under control by the control computer 24, the holographic stereogramprinter 25 sequentially records images, corresponding to image datafurnished from the image data furnishing device 26, to a recordingmedium for hologram, loaded in the holographic stereogram printer 25, asstrip-shaped elementary holograms.

[0075] At this time, the control computer 24 controls a light exposureshutter and a recording medium feed mechanism etc, provided in theholographic stereogram printer 25, as will be explained subsequently.That is, the control computer 24 sens out control signals to theholographic stereogram printer 25 to control the opening/closure of thelight-exposure shutter or the feed operation of the recording medium forhologram by the recording medium feed mechanism.

[0076] Referring to FIG. 13, the holographic stereogram printer 25 isexplained in further detail. FIG. 13A is a top plan view of the entireoptical system of the holographic stereogram printer 25, and FIG. 13B isa side view of the object light portion of the optical system of theholographic stereogram printer 25.

[0077] Referring to FIG. 13A, the holographic stereogram printer 25includes a laser light source 31, for radiating laser light of a pre-setwavelength, a light-exposure shatter 32 arranged on the optical axis ofthe laser light L1 from the laser light source 31 and a half-mirror 33.

[0078] The light-exposure shatter 32 is controlled by the controlcomputer 24 and is closed and opened when a recording medium forhologram 30 is not exposed to light or is exposed to light,respectively. The half-mirror 33 is used for separating the laser lighttransmitted through the light-exposure shutter 32 into reference lightand object light. The light L3 reflected by the half-mirror 33 becomesthe reference light, whereas the light L4 transmitted through thehalf-mirror 33 becomes the object light.

[0079] On the optical axis of the light L3, reflected by the half-mirror33, there are arranged, as an optical system for reference light, acylindrical lens 34, a collimator lens 35, for collimating the referencelight, and a total reflection mirror 36, for reflecting the lightcollimated by the collimator lens 35.

[0080] The light reflected by the half-mirror 33 is first turned intodivergent light by the cylindrical lens 34 and then collimated by thecollimator lens 35. The collimated light is reflected by the totalreflection mirror 36 to fall on the recording medium for hologram 30.

[0081] On the optical axis of the light L4, transmitted through thehalf-mirror 33, there are arranged, as an optical system for the objectlight, a total reflection mirror 38, for reflecting the lighttransmitted through the half-mirror 33, a spatial filter 39, combinedfrom a convex lens and a pin-hole, a collimator lens 40 for collimatingthe object light, a display device 41, for displaying an image of anobject for recording, and a cylindrical lens 42 for condensing theobject light on the recording medium for hologram 30, in this order, asshown in FIGS. 13A and 13B.

[0082] The light L4, transmitted through the half-mirror 33, isreflected by the total reflection mirror 38 and turned by the spatialfilter 39 into diffused light from a point light source. The diffusedlight then is collimated by the collimator lens 40 to fall on thedisplay device 41. The display device 41 is a transmission type imagedisplay device, comprised of, for example, a liquid crystal panel, anddisplays an image corresponding to image data furnished from the imagedata furnishing device 26. The light transmitted through the displaydevice 41 is modulated in accordance with an image displayed on thedisplay device 41 to fall on the cylindrical lens 42.

[0083] The light transmitted through the half-mirror 33 is converged bythe cylindrical lens 42 in the transverse direction at a pre-set lightcollecting angle θ_(e). This converged light falls as the object lighton the recording medium for hologram 30. That is, in this holographicstereogram printer 25, the projected light from the display device 41falls on the recording medium for hologram 30 as the strip-shaped objectlight.

[0084] It is noted that the reference light and the object light arecaused to fall on one and the other surfaces of the recording medium forhologram 30, respectively. That is, the reference light is caused tofall on one of the surfaces of the recording medium for hologram 30 at apre-set angle of incidence, while the object light is caused to fall onthe other surface of the recording medium for hologram 30 at a rightangle. This causes the reference light and the object light to interferewith each other on the recording medium for hologram 30. The resultinginterference fringes are recorded as changes in the refractive index onthe recording medium for hologram 30.

[0085] The holographic stereogram printer 25 also includes a recordingmedium feed unit 43 for intermittently feeding the recording medium forhologram 30 under control by the control computer 24. Each time an imagecorresponding to the image data supplied from the image data furnishingdevice 26 is recorded as one elementary hologram on the recording mediumfor hologram 30, loaded in a pre-set state on the recording medium feedunit 43, the recording medium feed unit 43 intermittently feeds therecording medium for hologram 30 in an amount corresponding to anelementary hologram, based on the control signal from the controlcomputer 24. In this manner, images derived from the image datafurnished from the image data furnishing device 26 are sequentiallyrecorded on the recording medium for hologram 30 so as to be contiguousin the transverse direction.

[0086] In the holographic stereogram printer 25, the optical path lengthof the reference light falling on the recording medium for hologram 30after reflection by the half-mirror 33 is preferably of a substantiallyequal length to the optical path length of the object light transmittedthrough the half-mirror 33 to then fall on the recording medium forhologram 30. This increases the interference between the reference lightand the object light to improve the image quality of the holographicstereogram.

[0087] For improving the image quality of the holographic stereogram,obtained by the holographic stereogram printer 25, a diffusion plate maybe provided on the optical path of the object light. By arranging thediffusion plate on the optical path of the object light, noisecomponents in the object light are diffused, while the light intensitydistribution of the object light incident on the recording medium forhologram 30 becomes more uniform to improve the image quality of thegenerated holographic stereogram.

[0088] If the diffusion plate is provided in this manner, it ispreferred to arrange a mask having a strip-shaped opening registeringwith the shape of the elementary hologram between the diffusion plateand the recording medium for hologram 30. By arranging the mask in thismanner, redundant portions of the object light, diffused by thediffusion plate, are shielded by the mask, thus further improving theimage quality of the produced holographic stereogram.

[0089] For affording a viewing angle in the longitudinal direction tothe holographic stereogram, a one-dimensional diffusion plate may beprovided on the optical path of the object light for diffusing theobject light in the holographic stereogram printer 25. With theone-dimensional diffusion plate, provided on the optical path of theobject light, the object light is diffused in the longitudinaldirection, that is along the long-axis direction of the elementaryhologram, so that the produced holographic stereogram has a viewingangle in the longitudinal direction.

[0090] If the one-dimensional diffusion plate is provided in thismanner, a louver film having a fine screen-shaped lattice is preferablyprovided between the holographic stereogram 30 and the one-dimensionaldiffusion plate. By arranging the louver film in this manner, it ispossible to prevent the reference light transmitted through therecording medium for hologram 30 from being reflected by theone-dimensional diffusion plate to fall again on the recording mediumfor hologram 30.

[0091] The holographic stereogram generating unit 23 operates asfollows:

[0092] When preparing the holographic stereogram, the image datafurnishing device 26 sends out image data to the display device 41 ofthe holographic stereogram printer 25 to cause the image for lightexposure corresponding to the image data to be displayed on the displaydevice 41. At this time, the image data furnishing device 26 sends outto the control computer 24 a timing signal indicating the effect ofsending out image data to the display device 41 of the holographicstereogram printer 25.

[0093] On reception of the timing signal, the control computer 24 sendsout a control signal to the light-exposure shutter 32 to open thelight-exposure shutter 32 for a pre-set time. This exposes the recordingmedium for hologram 30 to light.

[0094] Of the laser light L2, radiated by the laser light source 31 andtransmitted through the light-exposure shutter 32, the light L3,reflected by the half-mirror 33, falls on the recording medium forhologram 30 as the reference light. The light L4, transmitted throughthe half-mirror 33, becomes the projected light, projecting the imagedisplayed on the display device 41. This projected light falls on therecording medium for hologram 30 as the object light. This records theimage for light exposure, displayed on the display device 41, on therecording medium for hologram 30 as the strip-shaped elementaryhologram.

[0095] When the recording of an image on the recording medium forhologram 30 comes to a close, the control computer 24 causes a controlsignal to be sent to the recording medium feed unit 43 to feed therecording medium for hologram 30 by one elementary hologram.

[0096] The above-described operation is repeated as the images forexposure displayed on the display device 41 are changed over in thesequence of the parallax image string. This sequentially records theimages for light exposure, corresponding to the image data supplied fromthe image data furnishing device 26, on the recording median forhologram 30, as strip-shaped elementary holograms.

[0097] Meanwhile, there are occasions wherein, in sequentially recordingthe elementary holograms in this manner, the recording medium forhologram 30 is subjected to slight vibrations. In such case, subsidenceof the vibrations is awaited each time the recording medium for hologram30 is fed, and the elementary holograms are recorded after thesubsidence of the vibrations.

[0098] Thus, in the present holographic stereogram generating unit 23,image data are sequentially supplied from the image data furnishingdevice 26 to the holographic stereogram printer 25, the images forexposure corresponding to the image data are sequentially displayed onthe display device 4, the light-exposure shutter 32 is opened for eachimage and the respective images are sequentially recorded on therecording medium for hologram 30 as the strip-shaped elementaryholograms. Since the elementary holograms are fed one elementaryhologram for each image, the elementary holograms are arrayed insuccession on the recording medium for hologram 30 in the transversedirection. This records the parallax image string, composed of pluralimages having the parallax information in the transverse direction, asplural elementary holograms consecutive to one another in the transversedirection, on the recording medium for hologram 30, thus yielding aholographic stereogram having the parallax in the transverse direction.

[0099] With the above-described holographic stereogram generatingsystem, the image data generating device 1 and the holographicstereogram generating device 2 are independent of each other, as shownin FIG. 5. Between these devices, data exchange occurs using apre-viewing-point conversion parallax image string data file. Thus, inthe above-described holographic stereogram generating system, it becomespossible to provide a studio for imaging the parallax image string and aprinting laboratory generating the holographic stereogram, independentlyof each other, as shown in FIG. 14. That is, the studio having the imagedata generating device 1 and the printing laboratory having theholographic stereogram generating device 2 can be provided independentlyof each other with data exchange therebetween via a recording medium orover a network.

[0100] In the above-described holographic stereogram generating system,viewing-point conversion processing is taken charge of by theholographic stereogram generating device 2. Alternatively, an image dataconversion device for performing the viewing point conversion processingmay be provided independently of the holographic stereogram generatingdevice 2. In this case, the data receiving unit 21 and the viewing pointconversion unit 22 of the holographic stereogram generating device 2 areprovided on the image data conversion device.

[0101] If the image data conversion device is provided as an independentdevice, it is possible to provide a studio used for imaging a parallaximage string, a data processing center having the image data conversiondevice responsible for viewing point conversion processing and aprinting laboratory used for formulating the holographic stereogram,independently of one another, and to effect data exchange therebetweenvia a recording medium or over a network. In this case, it is thepre-viewing-point conversion parallax image string data file that isdelivered from the studio to the data processing center, while it is thepost-viewing-point conversion parallax image string data file that isdelivered from the data processing center to the printing laboratory.

[0102] Viewing Point Conversion Processing

[0103] The viewing point conversion processing is hereinafter explainedwith reference to a specified example. Here, the viewing pointconversion processing on the parallax image string imaged in accordancewith the re-centering system is explained as an example.

[0104] In the re-centering system, the object 50 is fixed, a camera 50for imaging the object 50 is translated, a lens 52 of the camera 51 ismoved in agreement with the shooting position so that the image of theobject 50 will perpetually be at the center of the imaging plane and theobject 50 is imaged a number of times form different positions, as shownin FIG. 16. This yields a parallax image string having the parallax inthe transverse direction.

[0105] In the holographic stereogram, generated directly from theparallax image string of the object, the relative position between theviewing point of the camera 51 and the object 50 at the imaging time ismaintained in the reproduced image of the generated holographicstereogram. Therefore, if the parallax image string as shot as describedabove is directly used in formulating the holographic stereogram, thereproduced image Z is formed at a position recessed a distancecorresponding to the imaging distance at the time of imaging theparallax image string from the hologram plane Ha of the holographicstereogram H. Therefore, in this holographic stereogram H, distortion orblurring is produced in the reproduced image Z unless the image Z isviewed with the viewing point S set on the holographic plane Ha so thatthe distance d0 between the reproduced image Z and the viewing point Sof the viewer will be coincident with the distance from the object 50 tothe camera 51 at the time of imaging.

[0106] In particular, in a white reproduced holographic stereogram,reproduced with the white light, the remoter the imaging position of thereproduced image Z from the hologram plane Ha, the more the reproducedimage Z tends to be blurred. Thus, if the reproduced image Z is formedat a recessed position from the hologram plane Ha, the reproduced imageZ is blurred severely.

[0107] In this consideration, viewing point conversion processing isperformed on the parallax image string, obtained as described above, sothat the reproduced image Z will be formed in the vicinity of thehologram plane Ha, as shown in FIG. 4. That is, the parallax imagestring is processed with viewing point conversion processing so that thereproduced image Z will be formed in the vicinity of the hologram planeHa, and the holographic stereogram is formulated using the parallaximage string subjected to viewing point conversion processing. By thisviewing point conversion processing, the reproduced image Z is fixed inthe vicinity of the hologram plane Ha, as shown in FIG. 4, such that aclear reproduced image Z, suffering from distortion or blurring to alesser extent, can be produced even if the viewing point S is set at aposition remote from the hologram plane Ha.

[0108] Referring to FIGS. 17 and 18, a specified example of the viewingpoint conversion processing is explained in detail. FIGS. 17, 18illustrates the principle of performing viewing point conversionprocessing on a parallax image string made up of m images as shot by there-centering system, referred to below as an original parallax imagestring, to re-construct a new parallax image string made up of n images,referred to below as a parallax image string for light exposure.

[0109] The parallax image string for light exposure is a parallax imagestring used for generating the holographic stereogram. That is, theholographic stereogram generating unit 23 sequentially displays theimages of the parallax image string for light exposure, subjected to theviewing point conversion processing, on the display device 41, asdescribed above, to generate the holographic stereogram.

[0110] Although the example given here is such a one in which a parallaximage string obtained by the above-described re-centering system, thatis the original parallax image string, is subjected to viewing pointconversion processing to generate a new parallax image string, that isthe parallax image string for light exposure, the technique of theviewing point conversion processing used in the present invention is notlimited to the following example since any other suitable technique maybe used depending on the parallax image string to be subjected toviewing point conversion processing.

[0111] In FIG. 17, g11, g12, . . . , g1m denote images constituting theoriginal parallax image string, and the original parallax image string,made up of these images g11, g12, . . . , g1m are collectively denotedGD. Also, g21, g22, . . . , g2n denote images making up the parallaximage string for light exposure, the parallax image string for lightexposure, made up of these images g21, g22, . . . , g2n, arecollectively denoted GE.

[0112] In FIG. 17, there is shown the relative arrangement of respectivelight exposure points ep1, ep2, . . . , epn of the holographicstereogram H having a length Le along the parallax direction, therespective images g21, g22, , g2n making up the parallax image stringfor light exposure GE and the respective images g11, g12, . . . , g1mmaking up the original parallax image string GD. In these light exposurepoints ep1, ep2, . . . , epn of the holographic stereogram H, the imagesg21, g22, . . . , g2n making up the parallax image string for lightexposure GE are recorded as elementary holograms.

[0113] In FIG. 17, only three points ep1, ep2, epn are shown as lightexposure points for convenience in the drawing, there are, of course, nlight exposure points in the holographic stereogrami H, such that the nimages g21, g22, . . . , g2n making up the parallax image string forlight exposure GE are recorded as elementary holograms at the respectivedifferent light exposure points.

[0114] The number of the light exposure points corresponds to the numbern of the images making up the parallax image string for light exposureGE. The number of the light exposure points depends on the transversesize Le of the holographic stereogram H and on the pitch ΔLe of thelight exposure points, as represented by the following equation (1):

Le=n×ΔLe  (1)

[0115] That is, if the transverse size Le of the holographic stereogramH is 10 cm and the light exposure pitch is equal and is 0.2 mm, thenumber of the light exposure points is 500.

[0116] Meanwhile, the pitch ΔLe of the light exposure points is thepitch of the elementary holograms and is one of parameters prescribingthe resolution of the holographic stereogram H. That is, the smaller thepitch ΔLe of the light exposure points, the higher is the resolution ofthe holographic stereogram obtained.

[0117] In FIG. 17, ΔLc is the amount of movement of the camera 51 foreach amount of movement of the camera 51 at the time of imaging of theoriginal parallax image string GD, referred to below as the cameramovement pitch. It is noted that Lc denotes the stun of movements of thecamera 51 relative to the object 50 at the time of imaging of theoriginal parallax image string GD, referred to below as the imagingwidth, while d_(f) means the distance between the camera 51 and theobject 50 at the time of imaging of the original parallax image stringGD, referred to below as the imaging distance. On the other hand, d_(v)denotes the distance between the viewing point S of the viewer of theholographic stereogram H and the hologram plane Ha, referred to below asthe viewing point distance.

[0118] Although the pitch ΔLe of the light exposure points may be equalto the camera movement pitch ΔLc, these need not necessarily be equal toeach other. However, the viewing point distance d_(v) needs to be equalto the imaging distance d_(f).

[0119] In the light exposure points of the holographic stereogram H, theimages g21, g22, . . . , g2n are exposed to light at a pre-set lightexposure angle θ_(e).

[0120] It is assumed that the resolution of the respective images g11,g12, . . . , g1m making up the original parallax image string and theimages g21, g22, . . . , g2n making up the parallax image string forlight exposure is 640 pixels and 480 pixels in the longitudinaldirection and in the transverse direction, respectively. Although theseimages are of the resolution of 640 pixels by 480 pixels, by way of anexample, the number of pixels making up these images is arbitrary and isnot intended for limiting the invention.

[0121] In the viewing point conversion processing, the respective imagesg11, g12, g1m making up the original parallax image string GD areconverted in the viewing point position to re-construct plural images toformulate a parallax image string for light exposure GE. Specifically,the relation of correspondence between the images g11, g12, . . . , g1mmaking up the original parallax image string GD and the images g21, g22,. . . , g2n making up the parallax image string for light exposure GE isfound and the pixels are interchanged based on the relation ofcorrespondence thus found to re-construct the respective images imagesg21, g22, . . . , g2n of the parallax image string for light exposure GEfrom the respective g11, g12, . . . , g1m of the original parallax imagestring GD.

[0122] The pixels are interchanged with the slit-like pixel string of640 pixels in longitudinal length and 1 pixel in transverse length asthe smallest unit. That is, in the viewing point conversion processing,the required pixels are extracted from the g11, g12, . . . , g1m of theoriginal parallax image string GD on the pixel string basis tore-construct new images images g21, g22, . . . , g2n. By handling pluralpixels collectively at a time in interchanging the pixels, theprocessing required for viewing point conversion processing can bereduced more significantly than if the pixels are handlednon-collectively. Moreover, since the slit-like pixel string of 640pixels in longitudinal length and 1 pixel in transverse lengthrepresents the smallest unit of the parallax information, there is nofear of the parallax information being lost even if the pixels areinterchanged in this manner on the pixel string basis.

[0123] Referring to FIG. 18, the above-described viewing pointconversion processing is explained in more detail. FIG. 18 shows themanner in which the pixel g21, as one of the pixels making up theparallax image string for light exposure GE, is taken out andre-constructed from the original parallax image string GD.

[0124] In re-constructing the image g21, it is first assumed that theimage g21 is on a plane DV separated by the viewing point distance d_(v)from the holographic stereogram H. The image g21 has a pre-set imageangle θ_(e) with respect to the light exposure points ep1 associatedwith the image g21.

[0125] It is also assumed that the images g11, g12, . . . , g1m makingup the original parallax image string GD are on a plane DD separated bythe imaging distance d_(f) from the image g21. The images g11, g12, . .. , g1m making up the original parallax image string GD are arranged onthe plane DD so as to be in register with the viewing point position atthe time of imaging of the object 50

[0126] Let straight lines L1, L2, . . . , Lk, referred to below asmapping lines L1, L2, Lk, be straight lines interconnecting the lightexposure points ep1 associated with the image g21 and sampling pointsmp11, mp12, . . . , mp1k on the image g21. These sampling points mp11,mp12, . . . , mp1k correspond to the pixel string making up the imageg21, with the number of the sampling points k in the image g21corresponding to the number of pixels in the transverse direction, thatis the parallax direction, of the image g21. Therefore, if the image g21is 640 pixels by 480 pixels in the longitudinal direction and in thetransverse direction, respectively, k=480.

[0127] Based on the above mapping lines L1, L2, . . . , Lk, an imagehaving the viewing point closest to the viewing point in each of thesampling points mp11, mp12, . . . , mp1k is selected, from one samplingpoint to another, and an image string closest to the mapping line isselected from the selected image.

[0128] If, for example, a sampling point mp11 is considered, an imageg11 having the viewing point closest to the sampling point mp11 isselected from the images g11, g12, . . . , g1m making up the originalparallax image string GD. The mapping line L1, interconnecting the lightexposure point ep1 and the sampling point mp11 is extended to the planeDD. Then, from the sampling points op11, op12, . . . , op1j of the imageg11, the sampling point op1j, closest to the point of intersection ofthe mapping line L1 and the plane DD is selected. The image string,lying at the so-selected sampling point opj1, is extracted from theimage g11, and is mapped to the sampling point mp11 of the image g21.

[0129] In the example of FIG. 18, it is assumed that there existjsampling points for the images g11, g12, . . . , g1m making up theoriginal parallax image string GD. That is, there exist sampling pointsop11, op12, . . . , op1j for the image g11 of the original parallaximage string GD and sampling points op21, op22, . . . , op2j for theimage g12. Similarly, there exist j sampling points for each of theremaining images. These sampling points are associated with the imagestrings of the images g11, g12, . . . , g1m, with the numberj of thesampling points in each image corresponding to the number of pixels inthe transverse direction, that is the parallax direction, of the eachimage. Therefore, if the images g11, g12, . . . , g1m are each composedof 640 pixels by 480 pixels in the longitudinal direction and in thetransverse direction, respectively, k=480.

[0130] The above-described mapping is executed for the sampling pointsmp12, . . . , mp1k of the image g21 to re-construct a new image g21. Byexecuting the similar processing on the other light exposure points ep2,ep3, . . . , epn, the respective images g22, g23, . . . , g2n associatedwith the respective light exposure points are re-constructed. This givesthe re-constructed parallax image string with viewing point conversionprocessing, that is the parallax image string for light exposure GE.

[0131] A holographic stereogram is generated by sequentially displayingthe respective images g22, g23, . . . , g2mnaking up the parallax imagestring for light exposure GE, on the display device 41, as describedabove, and by recording the images as slit-shaped elementary hologramson the recording medium for hologram 30.

[0132] In the holographic stereogram, thus generated, the viewing pointis shifted, by the viewing point conversion processing, a distancecorresponding to the viewing point distance d_(v) from the hologramplane towards the viewer. In keeping therewith, the reproduced imagealso is shifted towards the viewer a distance corresponding to theviewing point distance d_(v) so as to be fixed on or near the hologramplane. Thus, with the present holographic stereogram, there may beproduced a reproduced image suffering from distortion or blurring to alesser extent.

[0133] Meanwhile, the viewing point conversion processing is realized byinterchanging pixel strings to form a new image. The interchangingsequence is the same, despite difference in the parallax image strings,if the parameters of the viewing point conversion processing remain thesame. Therefore, if, in the viewing point conversion processing, theviewing points etc of the original parallax image string remain thesame, there is no necessity of repeatedly performing the above-describedprocessing. Thus, it is possible to provide a table stating the pixelsequence interchanging sequence and to refer to this table tointerchange the pixel sequences.

[0134] That is, it suffices if the above-described viewing pointconversion processing, described above, is carried out only initially tofind the relation of correspondence between the pixel strings of theoriginal image and the pixel strings of the image for light exposure,this relation of correspondence is stored in an external storage device,such as a hard disc drive, and to refer to this relation ofcorrespondence in performing the second and the following viewing pointconversion processing operations. This eliminates repetition of thecomputation processing to improve the processing speed significantly.

[0135] Header File

[0136] The header file, attached to the parallax image string file or tothe parallax image string for light exposure, is hereinafter explainedby taking a specified example.

[0137] If, when carrying out the viewing point conversion processing toformulate the holographic stereogram, the parameters for imaging aparallax image string, those for the viewing point conversion processingand those concerning the holographic stereogram being generated are notmatched to one another, desired reproduced images cannot be obtainedfrom the holographic stereogram. According to the present invention, theparameters required for the respective processes are monisticallysupervised and header files are attached to the parallax image stringfile or the image file for light exposure for utilization in therespective processes. In the following explanation, it is assumed that aheader file attached to the parallax image string file and a header fileattached to the image file for light exposure are of the format commonto the two files.

[0138] It is assumed that, in the present example, the filename of therespective image files making up the parallax image string file havingthe attached header file is constituted by a letter string combined froma letter string common to the parallax image string files, a file numberand a file extender specifying the image data form. That is, thefilenames of respective image files making up the parallax image stringfile read holo0000.bmp, holo0001.bmp, . . . , holo0499.bmp, by way of anexample. On the other hand, the filenaines of respective image files areeach made up of a letter string common to the parallax image stringfile, file number and the file extender indicating the form of the imagedata. Specifically, the filenames ofrespective image files making up aparallax image string for light exposure read hesp0000.bmp,hsep0001.bmp, . . . , hsep0499.bmp, by way of an example.

[0139] Table 1 shows specified examples of the parameters stored in theheader file attached to the parallax image string file or the image filefor light exposure. Meanwhile, the parameters attached to the headerfile are not limited to those shown in Table 1, such that it is possibleto increase or decrease items if so desired. Specifically, in generatinga color holographic stereogram, it is desirable to provide items forparameters for realization the color matching. TABLE 1 header filepara_img.file_name para_img.date para_img.time para_img.num_img_filepara_img.file_type para_img.img_type hs_img.shooting_typehs_img.file_name hs_img.date hs_img.time hs_img.num_img_filehs_img.file_type hs.width hs.height hs.scr_width hs.scr_heighths.unit_hologram_pitch hs.exposure_angle cmra.scale cmra.view_anglecmra.view_distance cmra.track_length

[0140] The respective items of the header file shown in Table 1 areexplained. In the above header file, the “hs_img.file_name”,“hs_img.date”, “hs_img.time”, “hs_img.num_img_file” and the“hs_img.file_type” are left blank before viewing point conversionprocessing and entry is made for these items at the time of the viewingpoint conversion processing. Stated differently, these items are blankitems at the stage of the header file of the parallax image string fileand entry is made when the header file is to be that of the parallaximage string for light exposure.

[0141] In the “para_img.file_name”, a letter string specifying theparallax image string file corresponding to this header file is set. Forexample, the letter string common to the parallax image string, of thefilenames of the respective image files making up the parallax imagestring, is set. That is, if the filenames of the respective image filesmaking up the parallax image string file are holo0000.bmp, holo0001.bmp,. . . , holo0499.bmp, “holo” is set for the “para_img.file_name”.

[0142] In the “para_img.date”, the date of preparation of the parallaximage string file is set.

[0143] In the “para_img.time”, the time of preparation of the parallaximage string file is set.

[0144] In the “para_img.num_img_file”, the number of image filescontained in the parallax image string file is set. For example, if theparallax image string file is made up of 500 image files, “500” is setin the “para_img.num_img file”.

[0145] In the “para_img.file_type”, a letter string specifying the formof the image files making up the parallax image string file is set. Forexample, if the image files making up the parallax image string file areof the BMP form, the “BMP” is set in the “para_img.file_type”.

[0146] In the “para_img.img_type”, a letter string indicating how theparallax image string file has been generated is set. If, for example,the parallax image string file has been formulated on actually imagingan object, the “Real Image” is set in the “para_img.img_type”, whereas,if the parallax image string file has been formulated by computergraphics, “CG” is set in the “para_img.img_type”.

[0147] In the “para_img.shooting_type”, a letter string specifying themethod of imaging the parallax image string is set. For example, if theparallax image string is shot by the re-centering system, “re-centering”is set in the “para_img.shooting_type”. If the parallax image string isshot by the straight track system, “straight track” is set in the“para_img.shooting_type”. If the parallax image string is shot by thepanning system, “panning” is set in the “para_img.shooting_type”.Finally, if the parallax image string is shot by the rotating system,“rotating” is set in the “para_img.shooting_type”.

[0148] In the “hs_img.file_name”, a letter string specifying theparallax image string for light exposure corresponding to this headerfile is set. Specifically, a letter string common to the parallax imagestring for light exposure, among the filenames of the respective imagefiles making up the parallax image string for light exposure, is set.That is, if, for example, the filenames of the respective image filesmaking up the parallax image string for light exposure are hsep0000.bmp,hsep0001.bmp, hsep0499.bmp, “hsep” is set in the “hs_img.file_name”.

[0149] In the “hs_img.date”, the data of generation of the parallaximage string for light exposure is set.

[0150] In the “hs_img.time”, the time of generation of the parallaximage string for light exposure is set.

[0151] In the “hs_img.nwn_img_file”, the number of image files containedin the parallax image string file is set. For example, if the parallaximage string for light exposure is made up of 500 image files, the “500”is set in the “hs_img.num_imgfile”.

[0152] In the “hs_img.file_type”, a letter string indicating the form ofrespective image files making up the parallax image string for lightexposure is set. If, for example, the respective image files making upthe parallax image string for light exposure is of the BMP form, the“BMP” is set in the “hs_img.file_type”.

[0153] In the “hs.width”, the transverse width of the holographicstereogram to be generated is set.

[0154] In the “hs.height”, the height of the holographic stereogram tobe generated is set.

[0155] In the “hs.scr_width”, the transverse width of a display devicefor displaying an image for light exposure in the holographic stereogramprinter is set.

[0156] In the “hs.scr_height”, the height of a display device fordisplaying an image for light exposure in the holographic stereogramprinter is set.

[0157] In the “hs.unit_hologram_pitch”, the transverse width of anelementary hologram recorded on a holographic stereogram to be generatedis set.

[0158] In the “hs.exposure_angle”, a light collecting angle of theobject light at the time of light exposure of the recording medium forhologram is set.

[0159] In the “cmra.scale”, the ratio between the Le value in FIG. 17and the transverse width (hs.width) of the holographic stereogram to begenerated is set. If the size of the object and that of the reproducedimage of the holographic stereogram is equal to each other, thetransverse width (hs.width) of the holographic stereogram to begenerated becomes equal to the Le value in FIG. 17. However, if the sizeof the object differs from that of the reproduced image of theholographic stereogram, it is necessary to define the ratio of the Levalue in FIG. 17 to the transverse width (hs.width) of the holographicstereogram to be generated. Thus, the value of Le/hs.width is set in“cmra.scale”.

[0160] In the “cmra.view_angle”, the horizontal angle of field of thecamera used for imaging the parallax image string is set.

[0161] In the “cmra.view_distance”, the imaging distance at the time ofimaging of the parallax image string is set.

[0162] In the “cmra.track_length”, the movement distance of the cameraat the time of imaging of the parallax image string, that is a valueindicating the movement range of the viewing point of the parallax imagestring, is set.

[0163] In the above explanation, it is presupposed that a planarholographic stereogram is to be generated. However, the shape of theholographic stereogram is not limited to the planar shape, such that itcan, for example, be cylindrical. If the shape of the holographicstereogram is to be non-planar, the information on the shape of theholographic stereogram to be generated is required at the time ofprocessing for viewing point conversion. Therefore, the information onthe shape of the holographic stereogram generated is also added to theheader file.

[0164] If, for example, a cylindrical holographic stereogram is to begenerated, the information on the diameter of the cylindricalholographic stereogram to be generated is required in order to performviewing point conversion processing associated with the cylindricalholographic stereogram. Therefore, in order to formulate the cylindricalholographic stereogram, an item specifying the diameter of thecylindrical holographic stereogram to be generated is provided in theheader file.

[0165] If the above-described header file is added to the parallax imagestring, it is possible to perform viewing point conversion processingcorresponding to the parallax image string imaging and holographicstereogram generating conditions to re-construct the parallax imagestring for light exposure. If such header file is added to the parallaximage string for light exposure to construct the post-viewing-pointconversion parallax image string data file, the information on theparticular conditions under which the viewing point conversionprocessing has been executed and the relation of correspondence betweenthe parallax image string file and the image file for light exposure canbe known only from the post-viewing-point conversion parallax imagestring data file.

[0166] If the above-described header file is attached to the parallaximage string file or the image file for light exposure, the parallaximage string file generating side can be independent from the side ofperforming viewing point conversion processing on the parallax imagestring file for exploiting it. Therefore, if the studio for imaging theparallax image string is mounted at a site remote from the printinglaboratory for generating the holographic stereogram, as shown in FIG.10, data required by the printing laboratory can be delivered from thestudio to the printing laboratory to formulate the holographicstereogram.

What is claimed is:
 1. An image data processing system comprising: meansfor formulating images having parallax data, said images having parallaxdata being made up of a plurality of images of an object from differentviewing points; and data attachment means for attaching the informationnecessary for performing the viewing point conversion processing ofconverting the viewing points for the object on said images havingparallax data.
 2. The image data processing system according to claim 1wherein data of new images having parallax data, obtained on executingsaid viewing point conversion processing, are data of the images havingparallax data used for generating a holographic stereogram, saidinformation containing the information on the conditions for generatingthe holographic stereogram.
 3. A method for processing image datacomprising: generating images having parallax data, said images havingparallax data being made up of a plurality of images of an object fromdifferent viewing points; and attaching the information necessary forperforming the viewing point conversion processing of converting theviewing points for the object on said images having parallax data tosaid images having parallax data.
 4. The image data processing methodaccording to claim 3 wherein data of new images having parallax data,obtained on executing said viewing point conversion processing, are dataof the images having parallax data, as used for generating a holographicstereogram, said information containing the information on theconditions for generating the holographic stereogram.
 5. An image dataconverting system comprising: data receiving means for receiving imageshaving parallax data, said images having parallax data being made up ofa plurality of images of an object from different viewing points and theinformation necessary for performing the viewing point conversionprocessing of converting the viewing points for the object on saidimages having parallax data; and viewing point conversion means forperforming viewing point conversion processing, on the basis of saidinformation, on said images having parallax data, as received from saiddata receiving means.
 6. The image data converting system according toclaim 5 wherein data of new images having parallax data, obtained onexecuting said viewing point conversion processing, are data of theimages having parallax data, used for generating a holographicstereogram, said information containing the information on theconditions for generating the holographic stereogram.
 7. The image dataconverting system according to claim 5 wherein said data receiving meansreceives the images having parallax data and said information via arecording medium, or over a network.
 8. An image data converting methodcomprising: inputting images having parallax data, said images havingparallax data being made up of a plurality of images of an object fromdifferent viewing points, and the information necessary for performingthe viewing point conversion processing of converting the viewing pointsfor the object on said images having parallax data, to computingprocessing means; and performing viewing point conversion processing, onthe basis of said information, on said images having parallax data, bysaid computing processing means.
 9. The image data converting methodaccording to claim 8 wherein new images having parallax data, obtainedon executing said viewing point conversion processing, are the imageshaving parallax data, as used for generating a holographic stereogram,said information containing the information on the conditions forgenerating the holographic stereogram.
 10. A holographic stereogramprinting system comprising: data receiving means for receiving imageshaving parallax data, said images having parallax data being made up ofa plurality of images of an object from different viewing points, andthe information necessary for performing the viewing point conversionprocessing of converting the viewing points for the object on saidimages having parallax data; and viewing point conversion means forperforming viewing point conversion processing, on the basis of saidinformation, on said images having parallax data, as received from saiddata receiving means; and means for generating a holographic stereogramusing new images having parallax data, as obtained on executing viewingpoint conversion processing by said viewing point conversion means. 11.The holographic stereogram printing system according to claim 10 whereinsaid data receiving means receives said images having parallax data andsaid information via a recording medium or over a network.
 12. A methodfor generating a holographic stereogram comprising: inputting imageshaving parallax data, said images having parallax data being made up ofa plurality of images of an object from different viewing points, andthe information necessary for performing the viewing point conversionprocessing of converting the viewing points for the object on saidimages having parallax data, to computing processing means; performingviewing point conversion processing, on the basis of said information,on said images having parallax data, by said computing processing means,to produce new images having parallax data; and using said new imageshaving parallax data for generating a holographic stereogram.
 13. Acomputer-readable recording medium in which there are stored imageshaving parallax data, said images having parallax data being made up ofplural images of an object from different viewing points; and datarequired for executing the viewing point conversion processing ofconverting the viewing points for the object on said images havingparallax data.
 14. The computer-readable recording medium according toclaim 13 wherein the recording medium is a holographic stereogramrecording medium.
 15. A data transmission method comprising:collectively transmitting images having parallax data, said imageshaving parallax data being made up of a plurality of images of an objectfrom different viewing points, and the information necessary forperforming the viewing point conversion processing of converting theviewing points for the object on said images having parallax data. 16.The data transmission method according to claim 15 comprising: inputtingimages having parallax data, and the information necessary forperforming the viewing point conversion processing of converting theviewing points for the object on said images having parallax data, tocomputing processing means; and performing viewing point conversionprocessing, on the basis of said information, on said images havingparallax data, by said computing processing means; and transmitting newimages having parallax data, as obtained on executing said viewing pointconversion processing.